Organic fibers impregnated with dinitrosoamines



H ORGANIC FIBERS IMPREGNATED WITH 7 mmrnosoammns Ching C. Tung, Kirkwood, Mo., assignor to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Filed Mar. 7, 1957, Ser. No. 644,458 11 Claims. 0. 154-139 The present invention relates to a new and improved method for the treatment of fibers. More particularly the invention relates to a method of obtaining improved adhesion ,or bonding between rubber and various fibers, whether in the form of cord, yarn, fabric or filaments, as well as to the improved products thereby obtained. The invention is particularly applicable to the improvement in adhesion between rubber and natural fibers such as cotton and also between rubber and synthetic fibers such as rayon, nylon and the like. i i

A primary object of the invention is to improve the bonding of fibers to. ruber. A particular object is to pro 2,983,642 Patented May 9, 1961 Rubber compositions were prepared in the well known manner from the followingrecipes:

vide a chemical treatment for commercial rayon or nylon or other synthetic fibers for the purpose of increasing the adhesion of such fibers to natural or synthetic rubber in reinforced rubber products. .Another object is to pro vide impregnated fibers which adhere to rubber.

Many manufactured rubber articles include fibers in the composition in the form of a sheet, cord or even as filaments. Examples of such compositions are tires, belting, hose, soles and the like. Even under the most favorable bonding conditions heretofore possible, and particularly in service where repeated flexings of the composition occur, separation of the rubber and fiber often results, thereby causing a weakening and frequently a failure of the product. This situation has resulted in developing a demand for a satisfactory agent to improve the adhesion of this invention to provide such an agent. 7

in accordance with the present invention it has been found that treating a fiber with a nitrosoamino compound and particularly with an N,4-dinitroso-N-substituted aniline increases the adhesion to a rubber as well as imparting other valuable properties. The treating agent, as is hereinafter disclosed, is applied to the fiber by commonly employed processes such as by impregnating the fibers with a water dispersion or solution of the treating agent. The invention will be apparent and understood from the examples and description that follow.

. Rayon and nylon tire cord suitable for use in the manufacture of automobile tires were each treated with water dispersions ofa nitrosoa-rninocompound such as an N,4- dinitroso-N-substituted aniline. In all cases, the dispersion undertest was prepared by agitating 12 parts of the nitrosoamine or the-dinitroso compound with 88 parts of water containing ammonium caseinate equivalent to 2% by weight of the nitroso compound taken. The dispersion was obtained in any desirable manner, preferably by use of a Szegvari Attritor. The tire cord was led into and through the dispersion by passing it under an aluminum l d pp n in a body Qft di p nt n in an aluminum container. After the cord was pulled through the treating bath it was air dried. It may be squeegeed after leaving the bath but in practice it was found that this step is not essential. Furthermore, drying at elevated temperature, as for example under a bank of infrared lamps, is feasible if desired.

Parts by weight Base A Base B Hevea smoked sheets; G -S 1500 1 Carbon black; Zinc oxide Saturated hydrocarbon soitenen- Sulfur Stearic acidyl es Diphenylguanidine 2,2'-Dithiobis benzothiazole l Butadiene'styrene copolymer rubber containing 23.5% bound styrene s ee GR-S and GR1 Synthetic Rubbers, published by Federal Facihties Corporation, Washington 25, D. 0., Ofiice of Synthetic Rubber, Table 0, Revised 3-1-54.

The adhesion of the treated cord to these compositions was determined by placing the cord between sample por tions of the unvulcanized stock, vulcanizing the assembly and measuring the force necessary to pull out the cord. The test sample pieces were prepared by use of an improved mold delevoped after experience with the Armstrong mold. In order to avoid distortion of the rubber under stress, thicker rubber sections were used. Complete descriptions of the Armstrong mold are found in India Rubber World, May 1946, pages 213-219. The specimens were H shaped with the cross bar of the H representing cord extending through two sections of the rubber but the rubber was in the form of cylinders /2" in diameter and 1 in height. The mold was composed of four 5 x 18f sections with the top and bottom solid plates to retain the rubber in the cavities of the two perforated plates. The two halves of the inner section were 9 thick and contained two rows of 10 perforations. Cord channels about. 9 ran' lengthwise across the diameters of the perforations. Overflow channels deep were provided in both sections (at the top and hotbetween the cord or fabric and the rubber. It is an object tom of the cylinders) to equalize the pressure. I

The rubber compositions described hereinbefore as Base A and Base B were extruded and cut into lengths approximately equal to one-half the height of the cylinders and placed on one of the perforated plates. The treated cordwas placed across the samples, the second perforated plate, also filled with identical samples, was placed on top and the two. perforated plates so built up were placed between the solid plates and the completed assembly vulcanized by heating in a press for 30 minutes at 158 C.

The cord was put between each pair of cured cylinders to provide the H-shaped specimens, the sides of the H representing the rubber cylinders. Essentially the quantity measured was the force required to pull a single cord in the direction of its axis from a cylinder of rubber in which one strand of a cord of a given length was embedded. Thus, the quantity measured was the pounds shearing force acting across the cord to rubber interface. The adhesion preferably was measured by a. Dillon tester with a jaw speed of the tester moving 12 inches per m nu In the tables of results that follow, the quantity of the treating agent, that is the nitrosoamine as shown, absorbed by the cord was determined by weighingthe dry cord before and after treatment. Thus, the pickup of test material is the percentage by which the cord increased in weight. The pullout value is the pull needed to tear the cord loose from the rubber, while the adhesion coefficient is times the pullout value of the treated cord divided by the pullout value of the untreated cord.

Table l Rayon I HeveeBase.

' Pick- GR-S Base Test Compound up on Cord Per- Pullout Ad- Pullout Adcent Value hesion Value hesion by Wt. Lbs. Ooeffi Lbs. Coefficient cient Methyl N-(p-nitrosophenyl)-B-a1anlne 11.6 9.0 112 7.4 161 N-(2-Chloroa1lyl)- p-nltrosoaniline 6.7 12.9 103 H 7.6 133 3-(p-Nitrosoanilino)- propionamide. 9.0 14.0 131 9.7 159 N-(p-Nitrosopheny 3' B-alanine 6.0' 10.2 124 7. 7 117 2-(p'-Nitrosoanilino)- nitrosoaniline 10. 3 v 18. 0 164 14. 2 222 Methyl-N-nigoso-llgf- -n roso en nlanino p y 9.2 13.6 210 3- (N ,4-Dinitrosoanillno)-propionamlde. 6. 2 23. 1 175 17. 9 276 2-(N,4-Dinitrosoanilino)ethanol .a 8.7 20.3 154 20.0 308 N ,4-Dln1trosophenylfl-alaninen; 5.1 12.5 152 10.4 193 3-(N,4-Dinitrosov anl1ino)-proplonltrlle 11.0 21.9 199 17.7 g 300 Table 11 Nylon Pickup GR-B Base Test Compound on Cord Percent by Wt. Pullout Ad- Value hesi on Lbs. Ooefllclout N-(2-Chloroallyl)-p-nltrosoaniline 3.8 4 6.3 117 3-(p-Nitrosoanilino)propiouamide. 8. 7 7. 3 116 N-(p-Nitrosophenyl)-B-alanlne 5.5 5.6 104 2-(p-Nit1osoanilino)ethan0l 8. 7 9. 2 146 3- (p-Nitrosoanilino)-propionitrile 2. 8 5. 9 124 N-Methyl-N,4-dinitrosoaniline 8. 0 7. 2 150 3-(N,4-Dinitrosoanilino)-propionamide .1. 9 9.3 202 2-(N,4-Dinitros0ani1lno;ethanol 6. 7. 4 161 3-(N,4-Dlnitrosoanilino '-proplonltrile 8.3 14.2 245 The drying method followed in drying the treated cord seems not'to be a. critical factorsince 'substantially'the same results were obtained for pullout adhesion when the treated cord was dried by standing over night'at' room temperature 'or dried under conditions varying from 1 hour 'at'70 C. to 5 minutes'at 150 C. Other nitroso N substituted anilines in addition to 'those particularly mentioned in the various examples are within the invention described. Such compounds are N,4-dinitros'odiphenylamine, N-ethyl-N,4-dinitrosoaniline, N-butyl-NA- dinitrosoaniline, N (2-chloroallyl') -N,4-dinitrosoaniline, N-ethyl-NA-dinitro'so-m=phenetidine, N,4-dinitroso'- N propylaniline, 1-nitroso-4-(p-nitrosophenyl)piperazine. N, N'-dinitroso-N,N'-bis(p nitrosophenyl)ethylenediamine, N-heptyl-N,4-dinitrosoaniline and others.

It is intended to cover all changes and modifications of the examples of the invention herein chosen for purposes of disclosure which do not constitute departures from the spirit andscope of the invention.

This application is a continuation-in-part of copending application Serial No. 503 347, filed April 22,1955, now abandoned.

-What is claimed is:

1. The method of treating organic fiber to enhancethe adhesion thereof to rubber which comprises impregnating the organic fiber with nitroso aromatic amine containing nitroso radicals on both nitrogen and carbon in minor amount sufiicient to increase the adhesion selected from the group consisting of 1nit'roso-4-(p-nitrosophenyl) piperazine, N,N'-dinitroso-N,N'-bis .(p nitrosophenyl) ethylenediamine, N-ethyl-N,4-dinitroso-m-phenetidine and N,4-dinitroso-N-substituted aniline wherein the substit-' uent is selected from the group consisting of phenyl, alkyl, carboalkoxy substituted lower alkyl, carbamyl substituted lower alkyl, hydroxy substituted lower alkyl, cyano substituted-lower alkyl and chloroallyl.

2. The method of treating organic fiber to enhance the adhesion thereof to rubber which comprises impregnating the organic fiber with N,4-dinitroso-N-alkyl aniline in minor amount sufiicient to increase the adhesion.

; 3. The method of treating organic fiber to. enhance the adhesion thereof to rubber which comprises ,impreg-j nating the organic. fiber with N-methy1-N,4-dinitrosoaniline in minor amount suificient to increase the adhesion. 1 j

4. The method of treating organic fiber to enhance the adhesion thereof to rubber which comprises impregnating the organic fiber with 3-(N,4-dinitrosoanilino)propionamide in minor amount sufficient to increase the adhesion. 5. The method of treating organic fiber to enhance the adhesion thereof to rubber which comprises impregnating the organic fiber with N,4-dinitrosophenyl-B-a1anine in minor amount sufficient to increase the adhesion. I

. 6. The method of treating organic fiber to enhance the adhesion thereof to rubber which comprises impregnating the organic fiber with 3-(N,4-dinitrosoani1ino)propionitrile in minor amount sufficient to increase the adhesion. 7. The method of treating rayon the cord to increase the adhesion thereof to rubber which comprises impregnating the rayon cord with N-methyl-NA-dini trosoaniline in minor amount sufficient to increase the adhesion;

8. The method of treating nylon tire cord to increase the adhesion thereof to rubber which comprises impregna'ting the nylon cord with N-methyl-N,4-dinitrosoaniline in minor amount sufficient to increase the adhesion.

9. Fiber reinforced vulcanized rubber article's; said fiber being an organic fiber adhered to the vulcanized rubber by means of nitroso-aromatic amine containing nitroso radicals on both nitrogen and carbon selected from the group consisting of 1-nitroso 4-(p nitrosophenynpiper References Cited in the file of this patent I UNITED STATES PATENTS Sebrell Aug', 1, 19 36 2,050,197 Sebrell .'.'Aug. 4; 1 936 2, 8 '35,624 Cousins May 20, 1958 1 I FOREIGN PATENTS t 522,568 Great Britain June 21; 1940 

1. THE METHOD OF TREATING ORGANIC FIBER TO ENHANCE THE ADHESION THEREOF TO RUBBER WHICH COMPRISES IMPREGNATING THE ORGANIC FIBER WITH NITROSO AROMATIC AMINE CONTAINING NITROSO RADICALS ON BOTH NITROGEN AND CARBON IN MINOR AMOUNT SUFFICIENT TO INCREASE THE ADHESION SELECTED FROM THE GROUP CONSISTING OF 1-NITROSO-4-(P-NITROSOPHENYL) PIPERAZINE, N,N''-DINITROSO-N,N''-BIS-(P-NITROSOPHENYL) ETHYLENEDIAMINE, N-ETHYL-N,4-DINITROSO-M-PHENETIDINE AND N,4-DINITROSO-N-SUBSTITUTED ANILINE WHEREIN THE SUBSTITUENT IS SELECTED FROM THE GROUP CONSISTING OF PHENYL, ALKYL, CARBOALKOXY SUBSTITUTED LOWER ALKYL, CARBAMYL SUBSTITUTED LOWER ALKYL, HYDROXY SUBSTITUTED LOWER ALKYL, CYANO SUBSTITUTED LOWER ALKYL AND CHLOROALLYL. 